Question 1

If a = 60 cm,b = 80 cm,Q = -4.0 nC,and q = 1.5 nC,what is the magnitude of the electric field at point P?

Accepted Answer

A) 68 N/C 
B) 72 N/C 
C) 77 N/C 
D) 82 N/C 
E) 120 N/C 
A) 68 N/C 
B) 72 N/C 
C) 77 N/C 
D) 82 N/C 
E) 120 N/C

Question 2

Charge of uniform density (40 pC/m2)is distributed on a spherical surface (radius = 1.0 cm),and a second concentric spherical surface (radius = 3.0 cm)carries a uniform charge density of 60 pC/m2.What is the magnitude of the electric field at a point 4.0 cm from the center of the two surfaces?

Accepted Answer

A) 3.8 N/C 
B) 4.1 N/C 
C) 3.5 N/C 
D) 3.2 N/C 
E) 0.28 N/C 
A) 3.8 N/C 
B) 4.1 N/C 
C) 3.5 N/C 
D) 3.2 N/C 
E) 0.28 N/C

Question 3

A long nonconducting cylinder (radius = 12 cm)has a charge of uniform density (5.0 nC/m3)distributed throughout its column.Determine the magnitude of the electric field 5.0 cm from the axis of the cylinder.

Accepted Answer

A) 25 N/C 
B) 20 N/C 
C) 14 N/C 
D) 31 N/C 
E) 34 N/C 
A) 25 N/C 
B) 20 N/C 
C) 14 N/C 
D) 31 N/C 
E) 34 N/C

Question 4

The velocity of a particle (m = 10 mg,q = -4.0 $\mu$C)at t = 0 is 20 m/s in the positive x direction.If the particle moves in a uniform electric field of 20 N/C in the positive x direction,what is the particle's speed at t = 5.0 s?

Accepted Answer

A) 60 m/s 
B) 20 m/s 
C) 45 m/s 
D) 40 m/s 
E) 70 m/s 
A) 60 m/s 
B) 20 m/s 
C) 45 m/s 
D) 40 m/s 
E) 70 m/s

Question 5

Three 2.50 $\mu$C charges are placed on tiny conducting spheres at the ends of 1.00 m-long strings that are connected at 120$\degree$ angles as shown below.The magnitude,in N,of the tension in any one of the strings is

Accepted Answer

A) 1.88 * 10 - 2. 
B) 3.25*10 - 2. 
C) 3.75* 10 - 2. 
D) 6.50 *10 - 2. 
E) 7.50*10 - 2. 
A) 1.88 * 10 - 2. 
B) 3.25*10 - 2. 
C) 3.75* 10 - 2. 
D) 6.50 *10 - 2. 
E) 7.50*10 - 2.

Question 6

A spaceship encounters a single plane of charged particles,with the charge per unit area equal to$\sigma$.The electric field a short distance above the plane has magnitude ____ and is directed ____ to the plane.

Accepted Answer

A)  $\frac { \sigma } { 2 \varepsilon _ { 0 } }$ ,parallel 
B)  $\frac { \sigma } { 2 \varepsilon _ { 0 } }$ ,perpendicular 
C)  $\frac { \sigma } { \varepsilon _ { 0 } }$ ,parallel 
D)  $\frac { \sigma } { \varepsilon _ { 0 } }$ ,perpendicular 
E)  $\frac { 2 \sigma } { \varepsilon _ { 0 } }$ ,parallel 
A)  $\frac { \sigma } { 2 \varepsilon _ { 0 } }$ ,parallel 
B)  $\frac { \sigma } { 2 \varepsilon _ { 0 } }$ ,perpendicular 
C)  $\frac { \sigma } { \varepsilon _ { 0 } }$ ,parallel 
D)  $\frac { \sigma } { \varepsilon _ { 0 } }$ ,perpendicular 
E)  $\frac { 2 \sigma } { \varepsilon _ { 0 } }$ ,parallel

Question 7

A particle (m = 20 mg,q = -5.0$\mu$C)moves in a uniform electric field of 60 N/C in the positive x direction.At t = 0,the particle is moving 30 m/s in the positive x direction and is passing through the origin.Determine the maximum distance beyond x = 0 the particle travels in the positive x direction.

Accepted Answer

A) 25 m 
B) 20 m 
C) 15 m 
D) 30 m 
E) 60 m 
A) 25 m 
B) 20 m 
C) 15 m 
D) 30 m 
E) 60 m

Question 8

Two planes of charge with no thickness,A and B,are parallel and vertical.The electric field in the region between the two planes has magnitude $\frac { \sigma } { \varepsilon _ { 0 } }$ .The electric field in the region to the left of A and the electric field in the region to the right of B may have the magnitudes

Accepted Answer

A) 0,0. 
B)  $\frac { \sigma } { \varepsilon _ { 0 } }$ , $\frac { \sigma } { \varepsilon _ { 0 } }$ . 
C)  $\frac { 2 \sigma } { \varepsilon _ { 0 } }$ , $\frac { 2 \sigma } { \varepsilon _ { 0 } }$ . 
D) given in any answer above. 
E) given only in answer (a)or (b)above. 
A) 0,0. 
B)  $\frac { \sigma } { \varepsilon _ { 0 } }$ , $\frac { \sigma } { \varepsilon _ { 0 } }$ . 
C)  $\frac { 2 \sigma } { \varepsilon _ { 0 } }$ , $\frac { 2 \sigma } { \varepsilon _ { 0 } }$ . 
D) given in any answer above. 
E) given only in answer (a)or (b)above.

Question 9

If a = 60 cm,b = 80 cm,Q = -6.0 nC,and q = 4.0 nC,what is the magnitude of the electric field at point P?

Accepted Answer

A) 35 N/C 
B) 42 N/C 
C) 52 N/C 
D) 64 N/C 
E) 104 N/C 
A) 35 N/C 
B) 42 N/C 
C) 52 N/C 
D) 64 N/C 
E) 104 N/C

Question 10

If a = 3.0 mm,b = 4.0 mm,Q1 = 60 nC,Q2 =-80 nC,and q = 36 nC in the figure,what is the magnitude of the electric force on q?

Accepted Answer

A) 5.0 N 
B) 4.4 N 
C) 3.8 N 
D) 5.7 N 
E) 0.60 N 
A) 5.0 N 
B) 4.4 N 
C) 3.8 N 
D) 5.7 N 
E) 0.60 N

Question 11

Two concentric imaginary spherical surfaces of radius R and 2R respectively surround a positive point charge Q located at the center of the surfaces.When compared to the electric flux $\phi$ 1 through the surface of radius R,the electric flux $\phi$ 2 through the surface of radius 2R is

Accepted Answer

A)  $\Phi _ { 2 } = \frac { 1 } { 4 } \Phi _ { 1 }$ . 
B)  $\Phi _ { 2 } = \frac { 1 } { 2 } \Phi _ { 1 }$ . 
C) $\phi$ 2 = $\phi$ 1. 
D) $\phi$ 2 = 2$\phi$ 1. 
E) $\phi$ 2 = 4$\phi$ 1. 
A)  $\Phi _ { 2 } = \frac { 1 } { 4 } \Phi _ { 1 }$ . 
B)  $\Phi _ { 2 } = \frac { 1 } { 2 } \Phi _ { 1 }$ . 
C) $\phi$ 2 = $\phi$ 1. 
D) $\phi$ 2 = 2$\phi$ 1. 
E) $\phi$ 2 = 4$\phi$ 1.

Question 12

Two charged particles,Q1 and Q2,are a distance r apart with Q2 = 5Q1.Compare the forces they exert on one another when $\overrightarrow { \mathrm { F } } _ { 1 }$ is the force Q2 exerts on Q1 and $\overrightarrow { \mathrm { F } } _ { 2 }$ is the force Q1 exerts on Q2.

Accepted Answer

A)  $\overrightarrow { \mathrm { F } } _ { 2 }$ = 5 $\overrightarrow { \mathrm { F } } _ { 1 }$ . 
B)  $\overrightarrow { \mathrm { F } } _ { 2 }$ = -5 $\overrightarrow { \mathrm { F } } _ { 1 }$ . 
C)  $\overrightarrow { \mathrm { F } } _ { 2 }$ = $\overrightarrow { \mathrm { F } } _ { 1 }$ . 
D)  $\overrightarrow { \mathrm { F } } _ { 2 } = - \overrightarrow { \mathrm { F } } _ { 1 }$ 
E) 5 $\overrightarrow { \mathrm { F } } _ { 2 }$ = $\overrightarrow { \mathrm { F } } _ { 1 }$ . 
A)  $\overrightarrow { \mathrm { F } } _ { 2 }$ = 5 $\overrightarrow { \mathrm { F } } _ { 1 }$ . 
B)  $\overrightarrow { \mathrm { F } } _ { 2 }$ = -5 $\overrightarrow { \mathrm { F } } _ { 1 }$ . 
C)  $\overrightarrow { \mathrm { F } } _ { 2 }$ = $\overrightarrow { \mathrm { F } } _ { 1 }$ . 
D)  $\overrightarrow { \mathrm { F } } _ { 2 } = - \overrightarrow { \mathrm { F } } _ { 1 }$ 
E) 5 $\overrightarrow { \mathrm { F } } _ { 2 }$ = $\overrightarrow { \mathrm { F } } _ { 1 }$ .

Question 13

A 24-nC charge is distributed uniformly along the x axis from x = 2 m to x = 6 m.Which of the following integrals is correct for the magnitude (in N/C)of the electric field at x = +8 m on the x axis?

Accepted Answer

A)  $$\int _ { 2 } ^ { 6 } \frac { 54 d x } { ( 8 - x ) ^ { 2 } }$$ 
B)  $\int _ { 2 } ^ { 6 } \frac { 216 d x } { ( 8 - x ) ^ { 2 } }$ 
C)  $\int _ { 2 } ^ { 6 } \frac { 54 d x } { x ^ { 2 } }$ 
D)  $$\int _ { 2 } ^ { 6 } \frac { 216 d x } { x ^ { 2 } }$$ 
E) none of these 
A)  $$\int _ { 2 } ^ { 6 } \frac { 54 d x } { ( 8 - x ) ^ { 2 } }$$ 
B)  $\int _ { 2 } ^ { 6 } \frac { 216 d x } { ( 8 - x ) ^ { 2 } }$ 
C)  $\int _ { 2 } ^ { 6 } \frac { 54 d x } { x ^ { 2 } }$ 
D)  $$\int _ { 2 } ^ { 6 } \frac { 216 d x } { x ^ { 2 } }$$ 
E) none of these

Question 14

A uniform linear charge density of 7.0 nC/m is distributed along the y axis from y = 2 m to y = 5 m.Which of the following integrals is correct for the magnitude (in N/C)of the electric field at y = 0 on the y axis?

Accepted Answer

A)  $\int _ { 2 } ^ { 5 } \frac { 63 d y } { y ^ { 2 } }$ 
B)  $$\int _ { 2 } ^ { 5 } \frac { 21 d y } { y ^ { 2 } }$$ 
C)  $\int _ { 2 } ^ { 5 } \frac { 63 d y } { ( 5 - y ) ^ { 2 } }$ 
D)  $\int _ { 2 } ^ { 5 } \frac { 21 d y } { ( 5 - y ) ^ { 2 } }$ 
E) none of these 
A)  $\int _ { 2 } ^ { 5 } \frac { 63 d y } { y ^ { 2 } }$ 
B)  $$\int _ { 2 } ^ { 5 } \frac { 21 d y } { y ^ { 2 } }$$ 
C)  $\int _ { 2 } ^ { 5 } \frac { 63 d y } { ( 5 - y ) ^ { 2 } }$ 
D)  $\int _ { 2 } ^ { 5 } \frac { 21 d y } { ( 5 - y ) ^ { 2 } }$ 
E) none of these

Question 15

A point charge (-5.0 $\mu$C)is placed on the x axis at x = 4.0 cm,and a second charge (+5.0 $\mu$C)is placed on the x axis at x = -4.0 cm.What is the magnitude of the electric force on a third charge (+2.5 $\mu$C)placed on the y axis at y = 3.0 cm?

Accepted Answer

A) 90 N 
B) 45 N 
C) 54 N 
D) 72 N 
E) 36 N 
A) 90 N 
B) 45 N 
C) 54 N 
D) 72 N 
E) 36 N

Question 16

A 40-$\mu$C charge is positioned on the x axis at x = 4.0 cm.Where should a -60-$\mu$C charge be placed to produce a net electric field of zero at the origin?

Accepted Answer

A) -5.3 cm 
B) 5.7 cm 
C) 4.9 cm 
D) -6.0 cm 
E) +6.0 cm 
A) -5.3 cm 
B) 5.7 cm 
C) 4.9 cm 
D) -6.0 cm 
E) +6.0 cm

Question 17

A point charge Q is placed on the x axis at x = -2.0 m.A second point charge,-Q,is placed at x = 1.0 m.If Q = 60 $\mu$C,what is the magnitude of the electrostatic force on a 40-$\mu$C charge placed at the origin?

Accepted Answer

A) 16 N 
B) 27 N 
C) 32 N 
D) 11 N 
E) 3.0 N 
A) 16 N 
B) 27 N 
C) 32 N 
D) 11 N 
E) 3.0 N

Question 18

Imagine for a minute that the Moon is held in its orbit about the Earth by electrical forces rather than by gravitation.What electrical charges -Q on the Earth and +Q on the Moon are necessary to hold the Moon in a circular orbit with a period of 27.3 days? The Earth-Moon distance is 384 000 km and the mass of the Moon is 7.35 * 1022 kg.

Accepted Answer

Q = 5.73 *

Question 19

An constant electric field, $$\overrightarrow { \mathbf { E } } = ( 3 \tilde { \mathbf { i } } + 4 \hat { \mathbf { j } } )$$ N/C,goes through a surface with area $$\overrightarrow { \mathbf { A } } = ( 8 \hat { \mathbf { i } } - 6 \hat { \mathbf { k } } )$$ m2.(This surface can also be expressed as an area of 10 m2 with the direction of the unit vector ( $0.8 \tilde { \mathbf { i } } - 0.6 \tilde { \mathbf { k } }$ ).What is the magnitude of the electric flux through this area?

Accepted Answer

A) 24 N . m2/C 
B) 48 N . m2/C 
C) 0.24 N . m2/C 
D) 0.48 N . m2/C 
E) 0 
A) 24 N . m2/C 
B) 48 N . m2/C 
C) 0.24 N . m2/C 
D) 0.48 N . m2/C 
E) 0

Question 20

If Q = 20 $\mu$C and L = 60 cm,what is the magnitude of the electrostatic force on any one of the charges shown?

Accepted Answer

A) 25 N 
B) 19 N 
C) 15 N 
D) 9.1 N 
E) 14 N 
A) 25 N 
B) 19 N 
C) 15 N 
D) 9.1 N 
E) 14 N

Exam 19: Electric Forces and Electric Fields

If a = 60 cm,b = 80 cm,Q = -4.0 nC,and q = 1.5 nC,what is the magnitude of the electric field at point P?

Charge of uniform density (40 pC/m2)is distributed on a spherical surface (radius = 1.0 cm),and a second concentric spherical surface (radius = 3.0 cm)carries a uniform charge density of 60 pC/m2.What is the magnitude of the electric field at a point 4.0 cm from the center of the two surfaces?

A long nonconducting cylinder (radius = 12 cm)has a charge of uniform density (5.0 nC/m3)distributed throughout its column.Determine the magnitude of the electric field 5.0 cm from the axis of the cylinder.

The velocity of a particle (m = 10 mg,q = -4.0 μ\muμ C)at t = 0 is 20 m/s in the positive x direction.If the particle moves in a uniform electric field of 20 N/C in the positive x direction,what is the particle's speed at t = 5.0 s?

Three 2.50 μ\muμ C charges are placed on tiny conducting spheres at the ends of 1.00 m-long strings that are connected at 120 °\degree° angles as shown below.The magnitude,in N,of the tension in any one of the strings is

A spaceship encounters a single plane of charged particles,with the charge per unit area equal to σ\sigmaσ .The electric field a short distance above the plane has magnitude ____ and is directed ____ to the plane.

If a = 60 cm,b = 80 cm,Q = -6.0 nC,and q = 4.0 nC,what is the magnitude of the electric field at point P?

If a = 3.0 mm,b = 4.0 mm,Q1 = 60 nC,Q2 =-80 nC,and q = 36 nC in the figure,what is the magnitude of the electric force on q?

Two concentric imaginary spherical surfaces of radius R and 2R respectively surround a positive point charge Q located at the center of the surfaces.When compared to the electric flux ϕ\phiϕ 1 through the surface of radius R,the electric flux ϕ\phiϕ 2 through the surface of radius 2R is

Two charged particles,Q1 and Q2,are a distance r apart with Q2 = 5Q1.Compare the forces they exert on one another when F→1\overrightarrow { \mathrm { F } } _ { 1 }F1​ is the force Q2 exerts on Q1 and F→2\overrightarrow { \mathrm { F } } _ { 2 }F2​ is the force Q1 exerts on Q2.

A 24-nC charge is distributed uniformly along the x axis from x = 2 m to x = 6 m.Which of the following integrals is correct for the magnitude (in N/C)of the electric field at x = +8 m on the x axis?

A uniform linear charge density of 7.0 nC/m is distributed along the y axis from y = 2 m to y = 5 m.Which of the following integrals is correct for the magnitude (in N/C)of the electric field at y = 0 on the y axis?

A point charge (-5.0 μ\muμ C)is placed on the x axis at x = 4.0 cm,and a second charge (+5.0 μ\muμ C)is placed on the x axis at x = -4.0 cm.What is the magnitude of the electric force on a third charge (+2.5 μ\muμ C)placed on the y axis at y = 3.0 cm?

A 40- μ\muμ C charge is positioned on the x axis at x = 4.0 cm.Where should a -60- μ\muμ C charge be placed to produce a net electric field of zero at the origin?

A point charge Q is placed on the x axis at x = -2.0 m.A second point charge,-Q,is placed at x = 1.0 m.If Q = 60 μ\muμ C,what is the magnitude of the electrostatic force on a 40- μ\muμ C charge placed at the origin?

If Q = 20 μ\muμ C and L = 60 cm,what is the magnitude of the electrostatic force on any one of the charges shown?

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Charge of uniform density (40 pC/m²)is distributed on a spherical surface (radius = 1.0 cm),and a second concentric spherical surface (radius = 3.0 cm)carries a uniform charge density of 60 pC/m².What is the magnitude of the electric field at a point 4.0 cm from the center of the two surfaces?

A long nonconducting cylinder (radius = 12 cm)has a charge of uniform density (5.0 nC/m³)distributed throughout its column.Determine the magnitude of the electric field 5.0 cm from the axis of the cylinder.

The velocity of a particle (m = 10 mg,q = -4.0 $\mu$ C)at t = 0 is 20 m/s in the positive x direction.If the particle moves in a uniform electric field of 20 N/C in the positive x direction,what is the particle's speed at t = 5.0 s?

A spaceship encounters a single plane of charged particles,with the charge per unit area equal to $\sigma$ .The electric field a short distance above the plane has magnitude and is directed to the plane.

If a = 3.0 mm,b = 4.0 mm,Q₁ = 60 nC,Q₂ =-80 nC,and q = 36 nC in the figure,what is the magnitude of the electric force on q?

Two concentric imaginary spherical surfaces of radius R and 2R respectively surround a positive point charge Q located at the center of the surfaces.When compared to the electric flux $\phi$ ₁ through the surface of radius R,the electric flux $\phi$ ₂ through the surface of radius 2R is

Two charged particles,Q₁ and Q₂,are a distance r apart with Q₂ = 5Q₁.Compare the forces they exert on one another when $\overrightarrow { \mathrm { F } } _ { 1 }$ is the force Q₂ exerts on Q₁ and $\overrightarrow { \mathrm { F } } _ { 2 }$ is the force Q₁ exerts on Q₂.

A point charge (-5.0 $\mu$ C)is placed on the x axis at x = 4.0 cm,and a second charge (+5.0 $\mu$ C)is placed on the x axis at x = -4.0 cm.What is the magnitude of the electric force on a third charge (+2.5 $\mu$ C)placed on the y axis at y = 3.0 cm?

A 40- $\mu$ C charge is positioned on the x axis at x = 4.0 cm.Where should a -60- $\mu$ C charge be placed to produce a net electric field of zero at the origin?

A point charge Q is placed on the x axis at x = -2.0 m.A second point charge,-Q,is placed at x = 1.0 m.If Q = 60 $\mu$ C,what is the magnitude of the electrostatic force on a 40- $\mu$ C charge placed at the origin?

If Q = 20 $\mu$ C and L = 60 cm,what is the magnitude of the electrostatic force on any one of the charges shown? $If Q = 20 \mu C and L = 60 cm,what is the magnitude of the electrostatic force on any one of the charges shown?$